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2. Quartzite - Wikipedia

   en.wikipedia.org/wiki/Quartzite

   Quartzite is a very hard rock composed predominantly of an interlocking mosaic of quartz crystals. The grainy, sandpaper-like surface is glassy in appearance. Minor amounts of former cementing materials, iron oxide, silica, carbonate and clay, often migrate during recrystallization, causing streaks and lenses to form within the quartzite. [1]

3. Quartz - Wikipedia

   en.wikipedia.org/wiki/Quartz

   Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide ). The atoms are linked in a continuous framework of SiO 4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO 2. Quartz is, therefore, classified structurally as a framework silicate mineral and ...

4. Quartz inversion - Wikipedia

   en.wikipedia.org/wiki/Quartz_inversion

   The room-temperature form of quartz, α-quartz, undergoes a reversible change in crystal structure at 573 °C to form β-quartz. This phenomenon is called an inversion, and for the α to β quartz inversion is accompanied by a linear expansion of 0.45%. This inversion can lead to cracking of ceramic ware if cooling occurs too quickly through ...

5. Carrara marble - Wikipedia

   en.wikipedia.org/wiki/Carrara_marble

   Sample sheets, 2016. Carrara marble, or Luna marble to the Romans, is a type of white or blue-grey marble popular for use in sculpture and building decor. It has been quarried since Roman times in the mountains just outside the city of Carrara in the province of Massa and Carrara in the Lunigiana, the northernmost tip of modern-day Tuscany, Italy.

6. Cristobalite - Wikipedia

   en.wikipedia.org/wiki/Cristobalite

   Specimen from California, US; size: 5.9 cm × 3.8 cm × 3.8 cm (2.3 in × 1.5 in × 1.5 in). Cristobalite ( / krɪˈstoʊbəˌlaɪt /) is a mineral polymorph of silica that is formed at very high temperatures. It has the same chemical formula as quartz, SiO 2, but a distinct crystal structure. Both quartz and cristobalite are polymorphs with ...

7. Category:Quartz varieties - Wikipedia

   en.wikipedia.org/wiki/Category:Quartz_varieties

   Varieties of the mineral Quartz. Subcategories. This category has the following 2 subcategories, out of 2 total. C. Chert‎ (3 C, 23 P) Q. Quartz gemstones‎ (2 C ...